From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hannes Reinecke Subject: Re: dm-multipath test scripts Date: Sat, 20 Feb 2016 10:42:16 +0100 Message-ID: <56C834F8.8050604@suse.de> References: <20151007053923.GA10749@xzibit.linux.bs1.fc.nec.co.jp> <20160218171745.GA15071@redhat.com> <56C662F1.8070407@ce.jp.nec.com> <56C6D45A.6060407@ce.jp.nec.com> <20160219194216.GB21133@redhat.com> <20160220061247.GA23333@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20160220061247.GA23333@redhat.com> Sender: linux-scsi-owner@vger.kernel.org To: Mike Snitzer , Junichi Nomura Cc: device-mapper development , linux-scsi List-Id: dm-devel.ids On 02/20/2016 07:12 AM, Mike Snitzer wrote: > On Fri, Feb 19 2016 at 2:42pm -0500, > Mike Snitzer wrote: > >> On Fri, Feb 19 2016 at 3:37am -0500, >> Junichi Nomura wrote: >> >>> On 02/19/16 09:33, Nomura Junichi wrote: >>>> On 02/19/16 02:17, Mike Snitzer wrote: >>>>> What is the last kernel version that your scripts have worked on? >>>> >>>> v4.4 worked fine. I'll check with v4.5-rc4 when I get a machine. >>> >>> v4.5-rc4 works fine, too. >> >> Have you been running with blk-mq? >> Either by setting CONFIG_DM_MQ_DEFAULT or: >> echo Y > /sys/module/dm_mod/parameters/use_blk_mq >> >> I'm seeing test_02_sdev_delete fail with blk-mq enabled. > > I only see failure if I stack dm-mq ontop of old non-mq scsi devices = with: > > echo N > /sys/module/scsi_mod/parameters/use_blk_mq > echo Y > /sys/module/dm_mod/parameters/use_blk_mq > > If I use scsi-mq for the underlying devices all works fine (been test= ing > the latest dm-4.6 branch though, I'll go back and try stock 4.5-rc4 j= ust > to double check). > > But this makes me think the novelty of having dm-mq support stacking = on > non-blk-mq devices was misplaced. It is a senseless config. I'll > probably remove support for such stacking soon (next week). Hmm. I must admit I really, really don't like these 'once-and-for-all' parameter. ATM the only SCSI driver to support SCSI-mq properly are lpfc, virtio,=20 and fnic. None of the other driver have been modified, and I suspect th= e=20 performance might be less than stellar. So there will be configurations where one might want to run scsi-mq=20 alongside non-mq HBAs. I would really love to see to make that more granular so that these=20 configurations can run efficiently. I know Christoph is violently against it, but I don't really see any=20 solution presenting itself at the moment. Maybe a good topic for LSF ... Cheers, Hannes --=20 Dr. Hannes Reinecke zSeries & Storage hare@suse.de +49 911 74053 688 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 N=FCrnberg GF: J. Hawn, J. Guild, F. Imend=F6rffer, HRB 16746 (AG N=FCrnberg) -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html